Welding thermal characteristics analysis with numerical simulation for thin-wall parts assembly under different conditions

In order to analyze the welding thermal characteristics problem,the multiscale finite element(FE)model of T-shape thin-wall assembly structure for different thicknesses and the heat source model are established to emphatically study their welding temperature distributions under different conditions.Simultaneously,different welding technology parameters and welding directions are taken into account,and the fillet weld for different welding parameters is employed on the thin-wall parts.Through comparison analysis,the results show that different welding directions,welding thicknesses and welding heat source parameters have a certain impact on the temperature distribution.Meanwhile,for the thin-wall assembly structure of the same thickness,when the heat source is moving,the greater the moving speed,the smaller the heating area,and the highest temperature will decrease.Therefore,the welding temperature field distribution can be altered by adjusting welding parameters,heat source parameters,welding thickness and welding direction,which is conducive to reducing welding deformation and choosing an appropriate and optimal welding thickness of thin-wall parts and relative welding process parameters,thus improving thin-wall welding structure assembly precision in the actual large-size welding structure assembly process in future.

Finite element analysis on temperature field and residual stress of welding assembly for I-beam and end-plate

Based on full scale model of 1-beam and end-plate welding assembly with medium plate, welding temperature field and residual stress were simulated, infrared thermometers were employed to measure the real-time temperature Jbr verification purposes. Results show that the measured thermal cycle curves match well with the simulation result. Simulation results of welding residual stress indicate that the values of longitudinal and transverse stress on the upper surface of the plate are higher than the normal stress; higher tensile stresses exist at the end of the web weld toes and in the central area of the flange weld toes. The dangerous zones are located at the central areas of weld toes of the flange welds and near weld toes of the web welds.

Design and development of automatic systems for assembly welding muffler of Santana automobile

Two types of automatic systems.for assembly welding. Santana automobile muffler in mass production are suggested in this paper Such systems were aPPlied to manufacture at the beginning of 1995, and were approved to have high productivity and quality but low cost. It is an optimal selection for someone who manufacture automobile muffler or Similar productlons.

Mapping relationship analysis of welding assembly properties for thin-walled parts with finite element and machine learning algorithm

The finite element(FE)-based simulation of welding characteristics was carried out to explore the relationship among welding assembly properties for the parallel T-shaped thin-walled parts of an antenna structure.The effects of welding direction,clamping,fixture release time,fixed constraints,and welding sequences on these properties were analyzed,and the mapping relationship among welding characteristics was thoroughly examined.Different machine learning algorithms,including the generalized regression neural network(GRNN),wavelet neural network(WNN),and fuzzy neural network(FNN),are used to predict the multiple welding properties of thin-walled parts to mirror their variation trend and verify the correctness of the mapping relationship.Compared with those from GRNN and WNN,the maximum mean relative errors for the predicted values of deformation,temperature,and residual stress with FNN were less than 4.8%,1.4%,and 4.4%,respectively.These results indicate that FNN generated the best predicted welding characteristics.Analysis under various welding conditions also shows a mapping relationship among welding deformation,temperature,and residual stress over a period of time.This finding further provides a paramount basis for the control of welding assembly errors of an antenna structure in the future.

THE 47TH ANNUAL ASSEMBLY THE INTERNATIONAL INSTITUTE OF WELDING

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FLEXIBLE ASSEMBLY FIXTURING LAYOUT MODELING AND OPTIMIZATION BASED ON GENETIC ALGORITHM

There are many welding fixture layout design problems of flexible parts inbody-in-white assembly process, which directly cause body assemble variation. The fixture layoutdesign quality is mainly influenced by the position and quantity of fixture locators and clamps. Ageneral analysis model of flexible assembles deformation caused by fixture is set up based on'N-2-l' locating principle, in which the locator and damper are treated as the same fixture layoutelements. An analysis model for the flexible part deformation in fixturing is set up in order toobtain the optimization object function and constraints accordingly. The final fixture elementlayout could be obtained through global optimal research by using improved genetic algorithm, whicheffectively decreases fixture elements layout influence on flexible assembles deformation.

Improving the Use of Robotic Welding of Aluminum Boats through Modularization

The level of automation in the manufacture of recreational aluminum boats is very low. Robotized welding is rarely utilized, although it is commonly considered as the most effective way to reduce costs and increase competitiveness. A reason for the under-exploitation of robotics can be found in the construction of aluminum boats;boat models and their detailed structures are almost without exception individual pieces. A new stiffener structure for an aluminum recreational boat hull is developed in this work. Construction of the stiffener as a module allows exploitation of the advantages of modularization. The number of different parts is reduced and the structure simplified improves the applicability of robotic welding and provides benefits accruing from mass production. The same module can be used in several boat models. The modularity also makes it possible to use the same advanced robot welding fixture for a variety of boat models.

Research on Radial Friction Welding of 30 mm Shell's Band

A new radial friction welding technology of 30 mm shell's band is introduced.Bands are assembled to shell bodies without notches by using the process.The width of heat-affected zone(HAZ) is small,and the microstructure on steel side is incomplete quenching while that on cooper side is grain refining.The shear-strength of joint exceeds 200 MPa.The result of firing test indicates that radial friction welding can satisfy the assembly requirements of shell bands.

Characterization of Ultrasonic Metal Welding Process

The ultrasonic welding process for wires is being largely used on industry mainly on applications that involve the connectionbetween similar or different metals. The biggest benefit of this technology is the possibility to perform the weld without additionmaterials, like terminals, metal rings or tapes. Manufacturing of wiring harnesses demands a significant amount of joining, such aswelding, crimping or soldering, to fulfill the desired layout of the harnesses and capacity requirements, but conventional connectionprocesses, face difficulties in joining multiple cross sections mainly due to the characteristics of the processes and equipment in use.Ultrasonic metal welding process overcomes these issues due to the solid-state characteristics inherent to the process itself that includethe excellent electrical properties of the joint. Several researches on ultrasonic metal welding are being done to define the fundamentalmechanisms behind this process and it is being seen that they are completely dependent on the cross section to be welded. With thisresearch we are trying to develop methods for process characterization and define acceptable quality parameters in this process. Themain topics addressed in this paper are the characterization the weld formation using copper-to-copper wires using optical microscopyand the analysis of insulation material when submitted to different thermal conditions.

车架纵梁焊接变形控制在生产线中运用

车架总成运用在皮卡、轻卡和非承载式乘用车上,是非常重要的底部骨架件。车架总成质量对整车安全、舒适性影响较大。车架总成中纵梁总成的焊接变形最难控制,传统的控制焊接变形方式已经很难保证纵梁总成变形量,使得车架整体尺寸控制和装配都难达到高品质要求,为了提升车架总成尺寸,降低车架纵梁总成焊接变形量,本文对车架纵梁总成焊后变形进行研究,从夹具设计和机器人焊接布局两方面来保证纵梁总成焊后变形控制在2.3-3.2mm,从而保证车架总成尺寸和生产效率。

大型轴向列管式固定床反应器的设计、制造、运输

通过对大型轴向列管式固定床反应器的列管布置、管板强度计算、支持板结构、管板的焊接及热处理、壳体组装、运输等多方面优化,从设计、制造、运输三方面综合考虑,使大型轴向固定床反应器的本质安全、运行效果达到更高的要求。

基于Inventor的船舶钢架焊接装配有限元研究

利用Inventor软件对船舶钢架焊接装配进行静态有限元分析研究。分析结果揭示钢架焊接装配后的最大最小Mises等效应力、第一主应力、第三主应力、安全系数、应变、位移、接触压力等数值分布及其规律。对比船舶钢架结构焊接装配后的钢结构型材变形与收缩数值。在实际生产过程中,应控制在数值范围内取其平均值进行焊接装配。这种焊接方式在一定程度上可以提高型材的使用寿命,减少磨损腐蚀,具有广泛的推广价值,为大型船舶钢架焊接装配工艺数值模拟研究提供有益参考。

深孔焊结构喷泉式管束装配工艺技术研究

深孔焊技术广泛应用于石油化工领域中的重要换热设备,可有效减少间隙腐蚀、应力腐蚀、疲劳破裂等问题。本文针对深孔焊结构喷泉式管束,进行装配工艺技术的研究。

船用齿轮箱输入轴组件加工变形控制

分析了船用齿轮箱输入轴组件的制坯、薄壁件热处理变形控制方法,以及电子束焊变形的控制方法,为解决船用齿轮箱输入轴组件的制造难题,提供了很好的解决方案。

汇流环人机协同产线设计与实践

文中对汇流环的结构特点进行了梳理,通过分析汇流环的装配工艺流程,结合工艺特点建立了部件装配、整件装配和跑合测试的装配作业单元。根据各装配单元的工作内容和控制要点分别设计了焊接平台、一体化装配平台和智能跑合台。通过工艺装备的使用,将传统的手工装配作业模式升级为人机协同的工作模式,对导电环焊接参数、跑合参数等装配过程关键要素进行控制和记录。在降低装配作业强度、提高工作效率的同时,显著提升了质量可追溯性。

船用T型材装焊生产线的研发与应用

针对当前船用T型材生产量大、人员投入多、生产工序多等问题,设计一套T型材自动化装焊生产线,通过对产线各功能模块的自动化,实现T型材的自动进料、自动除漆倒角、自动装配、自动焊接、自动矫直等。通过T型材生产线的研发,可以有效提高T型材的生产效率,减少相关作业人员,稳定T型材装配及焊接质量,进而提高整条船的生产效率及质量。

聚乙烯管焊接接头相控阵超声检测的优化设计

在管道工程应用中,由于良好的耐腐蚀性和韧性,聚乙烯(PE)管与其他材料相比具有显着优势,已广泛地应用在核电、油气输送领域;PE管焊接过程中,焊接参数、人员操作和环境等因素会影响聚乙烯管道的焊接情况,可能致使焊接接头内部形成缺陷,影响管道安全运行,而相控阵超声检测技术能够实现聚乙烯管道焊接接头内部结构的无损检测及评估;因此开展PE管焊接接头的相控阵超声实际检测工作,研究了聚乙烯材料的声衰减规律及声频散效应,优化了焊接接头的超声相控阵检测工艺,基于CIVA仿真软件实现了聚乙烯管道相控阵超声检测的声场模拟和缺陷仿真,通过研究检测参数及声学参量变化对检测结果的影响,获得了PE管焊接接头的最优检测工艺;通过加工带有典型缺陷的聚乙烯热熔对接接头试样,对前期基于仿真结果设计的检测工艺以及针对焊接接头相控阵检测研发的楔形耦合组件进行可靠性测试和工艺试验;研究结果为PE管接头缺陷的超声相控阵检测提供了工艺设计的理论支持和可靠的研究方法。

精密加速度计组件自动装配及焊接系统

悬丝摆式加速度计广泛应用于航空、航天、惯性导航等领域,其装配质量对加速度测量精度有很大的影响,其关键组件的装配涉及位置和姿态的调整,同时悬丝在装配中需要控制张紧力并完成焊接。针对悬丝摆式加速度计组件的精密装配,研发了集成力、温度传感器和机器视觉的精密装配及焊接系统。采用相机配合转台实现待装配零件视觉测量,完成零件特征点的识别定位;利用精密滑台和转台调整待装配零件位姿;直线电机运动结合力反馈实现装配过程中零件间隙调整以及张紧力控制;开发专用焊接单元,实现在紧凑空间内对微小器件的自动温控焊接。试验结果表明,该系统能够完成加速度计组件自动装配及焊接,装配结果满足技术指标要求,焊点无虚焊,摆组件内边缘相对于磁钢边缘间隙偏差小于10μm,悬丝中心相对于加速度计底座地面位置精度优于20μm,悬丝张紧力偏差控制在±5 mN之内,能够达到产品装配质量要求。

装配间隙对铝合金激光-电弧复合焊接头成形及气孔的影响研究

采用激光先导方式的激光-电弧复合焊对高速列车车体常用的6082-T6铝合金锁底接头进行焊接试验。通过改变水平间隙和竖直间隙的大小,研究其对焊缝成形、熔深熔宽和气孔率的影响,并结合Fluent数值模拟软件进行验证。结果表明,随着水平间隙的增加,焊接接头的熔深和熔宽都呈现逐渐增大的趋势,特别地,当水平间隙从0 mm增大到1.2 mm时,熔深和下部熔宽分别从5.91 mm和1.65 mm增加至6.45 mm和2.46 mm,这主要归因于激光焊接热输入的增大;另外,接头气孔率呈现先下降后上升的趋势,当水平间隙为0.7 mm时,气孔率达到最小,仅为9.21%,小于无间隙时的10.86%和间隙为1.2 mm时的12.61%,这说明一定的水平间隙尺寸有利于提高匙孔稳定性,而过大的水平间隙尺寸则会造成匙孔稳定性变差;另外,随着竖直间隙的增加,尽管接头的熔深熔宽无明显变化,但气孔率呈现不断增大的趋势,从10.86%增大到15.85%,说明竖直间隙的存在不利于维持熔池匙孔的稳定性。最佳装配间隙尺寸为:水平间隙0.7 mm和竖直间隙0 mm。本研究将为采用激光-电弧复合焊接技术来实现高速列车用铝型材的高质量焊接提供工艺指导,并扩大激光-电弧复合焊接在相关领域的应用范围。

150m跨整孔全焊接钢桁梁试拼装工艺及荷载试验研究

孟加拉帕德玛大桥上部为全焊接连续钢桁梁结构,施工中开创性地采用了整孔拼装及架设方案。为验证钢桁梁拼装过程中线形计算及拼装方案的合理性、可行性,选取1跨钢桁梁进行试拼装和荷载试验。详细阐述了钢桁梁试拼装前线形计算、整孔试拼装施工技术、荷载试验等相关内容,通过对全过程检测数据及荷载试验分析,验证了该钢桁梁线形计算结果、拼装技术及试验结果均满足要求。